The analysis of magnetic and electrical transport properties is a rapidly growing field with a wide range of applications such as low loss electronics, sensors or future compute components. Our tests can be run in extreme environments at a temperature and magnetic field range of 1.8K-400K and 0T-9T respectively. There are many reasons why someone might need an analysis of the magnetic and electrical transport properties of materials and devices in a controlled environment. Here are a few examples:
NPL can offer analysis of the magnetic and electrical transport properties of materials and devices in a controlled environment. The magnetic field and temperature can be precisely controlled, and the analysis can be performed on bulk, thin film, powder samples and electronic devices.
This capability would be of interest to those working on next generation low loss electronics.
The system at NPL is designed to measure the physical properties of materials in a variety of forms. A requirement is that the sample is small enough to fit within the measurement volume of the instrument.
Precise control of the magnetic field and temperature: This allows for accurate measurements of the magnetic and electrical properties of materials and devices.
Ability to measure bulk, thin film, and powder samples: This allows for a wide range of materials to be analysed.
Experienced staff: NPL's staff has extensive experience in measuring the physical properties of materials and devices.
NPL can use a Vibrating Sample Magnetometer (VSM) to measure a sample's magnetic moment as a function of temperature or magnetic field. The VSM is a fast, sensitive, and fully automated DC magnetometer. It works by oscillating the sample in a pickup coil and synchronously detecting the induced voltage.
The VSM uses a compact gradiometer pickup coil configuration, a relatively large oscillation amplitude (1-3 mm peak), and a frequency of 40 Hz. This allows the system to resolve magnetization changes of less than 10-6 emu at a data rate of 1 Hz.
Due to the size of the pickup coil, samples are currently limited to diameters and lengths of less than 4.5 mm and 5 mm, respectively. The diameter is physically limited by the bore of the pickup coil, while lengths in excess of 5 mm tend to produce a reduced moment that is best to avoid. Samples are mounted to either quartz paddles or brass troughs, as required.
Electrical transport measurements are typically limited to samples that are less than 10 mm x 10 mm in lateral extent and several millimetres in thickness. Powders are typically pressed into geometries (sometimes with the aid of binders) that satisfy these dimensional requirements. The currently available measurement options are:
Within the approximately 10 mm x 10 mm mounting area within the instrument, there is typically room for up to 3 samples, provided they are sized appropriately.
The Electrical Transport Option (ETO) enables AC electrical transport measurements of samples using a 2- or 4-probe lead configuration. The 2-probe configuration is suitable for all ranges of samples, while the 4-probe configuration is especially useful for looking at resistive samples, or those where pulsed current measurements could be utilized such as when studying memristors.
The 4-probe configuration is advantageous in terms of reducing the contribution of lead and contact resistances. With proper lead placement, the Hall coefficient can also be measured in 4-wire mode.
In addition to resistance and Hall coefficient, 2- and 4-wire current-voltage curves as well as differential resistance (dV/dI) can be measured. In 4-wire mode, the voltage response is measured in response to a current excitation. In 2-wire mode, the current response is measured in response to a voltage excitation.
The DC resistance option allows for resistance measurements on up to three channels using a standard puck. This option highlights the efficiency of the system, as it allows for full temperature and field sweeps of three samples to be taken simultaneously, reducing the time cost even further.
Contact a member of NPL's quantum team today to schedule a consultation. We can discuss your specific needs and how our quantum technologies can help you achieve your goals.